You Can’t Compost in Plastic Bags

Compost needs air and water

By Dr. Francis Gouin

I heard a garden advisor on radio tell his listeners to compost their leaves in plastic bags rather than placing them on the curb for pick-up by the municipality. Put the leaves in the plastic bag and dump in a pitcher of warm water with two to three packages of bakers yeast dissolved in the liquid, he advised.
I hope no one listened.
Composting is an aerobic process. The organisms involved are bacteria, fungi and actinomycetes. There are no yeasts in the composting process.

Don’t Stop Mowing Your Lawn

I also had bad news for the friend who told me he had already put away his lawnmower for the season. This is a big mistake. If we get lots of snow this winter and the grass is tall, it is highly likely he will have a bad case of snow-mold next spring.
Keep mowing your lawn until the snow flies. It is good for you to be outside and getting exercise, and you’re also helping your grass avoid disease problems.

The compost-making bacteria, fungi and actinomycetes require oxygen to function. Plastic garbage bags are made of polyethylene, which is impermeable to carbon dioxide. A sealed bag will result in the accumulation of carbon dioxide, which will replace the oxygen. The system will go anaerobic. If the bag is sealed tight, it could even explode. In addition to accumulating carbon dioxide, alcohol and acetic acid will accumulate in the bag. The odors will be sufficient to gag a maggot.
Many years ago, a friend was so proud of the composting bin that he built of brick and blocks that he invited me to see and appreciate his project. The wooden opening in the front of the bin was made of tight-fitting pressure-treated boards. The only portion of the composting bin open to the air was the top. To make things worse, he had built the composting bin on a slab of concrete. There was no way in the world that worms would ever enter his compost.
He was stunned when I told him to punch holes through the brick and block walls and to place spacers between the boards that closed the front opening.
Efficient compost bins can be made of wooden pallets. My compost bin is made of four-by-two-inch turkey fencing.
Make your compost bin no smaller than three-by-three feet and no more than six feet tall. It should be built on well-drained soil. It makes no difference if the bin is in the shade or full sun. Microbes don’t have eyes.
What is important is that the compost bin should be located where water can be easily added. The wider the compost bin the better. Larger compost bins remain active later in the fall because of the greater amount of mass they hold. Composting is more efficient at temperatures between 100 and 140 degrees. Greater mass results in better composting.
You can’t compost in plastic bags.